The present invention relates to a novel socket-type connector for electric connection in which electric connection is obtained by inserting a conductive pin plug into the socket.
In the prior art, various types of connectors are known for electrically connecting various kinds of semiconductor devices such as diodes, transistors, integrated circuits and the like as well as electronic circuit units with each other. Among them, socket-type connectors belong to one of the most popular classes of the connectors. A socket-type connector is constructed by providing one or more of contacting elements of a metal inside the pocket of a socket made of an insulating material and electric connection is obtained by inserting a pin plug of the device or circuit unit into the pocket through the mouth of the pocket. In the connectors of this type, the contacting element of metal is usually shaped in various forms something like a spring such that a resilient force is exhibited when the pin plug is inserted into the socket in order to ensure good electric connection between the pin plug and the contacting element and to prevent the pin plug from getting off the socket. In accordance with the shapes of the contacting elements and the pin plugs inserted thereinto, they are called a banana-chip type, pin-socket type, knife-plate type, tuning-fork type and the like.
One of the unavoidable problems in these prior art socket-type connectors, especially, when a miniature-sized connector is desired, is that fabrication of a large number of tiny contacting elements into spring-like forms and assembling of them in the sockets are very troublesome and time-consuming and cannot be very accurate so that the reliability and durability of such connectors are rather poor when, in particular, the pin plugs are repeatedly and frequently inserted into and pulled out of the socket-type connectors for electric connection and disconnection. This problem is more and more serious along with the growing trend for miniaturized or thin designs of electronic instruments.
An improvement for such a type of connectors has been recently proposed, for example, in U.S. Pat. No. 3,871,737, Japanese Patent Disclosure No. 50-86685 and Japanese Patent Publication No. 51-13232, in which an electroconductive rubber is used as a material for the contacting element coming into contact with the pin plugs. A problem in the connectors of this type using an electroconductive rubber is the relatively large contact resistance between the contacting element and the pin plug so that limitations are given in their use in a circuit with a relatively large electric current. Furthermore, frequent insertion and removal of the pin plug into and from the socket may sometimes lead to chipping off of the contacting element or even to complete loss of the element.